The formulation of detergent compositions containing typical detersive surfactants necessarily results in products which have, to a more or less degree, the inherent tendency to form suds when the compositions are agitated in an aqueous medium. In many circumstances, the formation of suds is desirable, and consumers have come to expect high, rich suds in various shampoo, personal cleansing and hand dishwashing compositions. On the other hand, in certain other compositions the presence of suds can be problematic. For example, most hard surface cleansers are designed to have low suds levels, thereby obviating the need for extensive rinsing of the surfaces after the cleanser has been applied. Likewise, some washing machines, especially European-style front-loading machines which are designed to use substantially less water than the more familiar American style top-loading machines, typically employ higher concentrations of detersive surfactants. Suds levels must be kept low or else the suds can actually spill from such machines. A similar situation occurs with most automatic dishwashing machines where surfactant levels are kept very low and suds controlling agents are used extensively to provide a nearly sudsless cleaning of dishware. Low sudsing can also be advantageous in concentrated laundering processes such as those described in U.S. Pat. Nos. 4,489,455 and 4,489,574.
Considerable attention has lately been directed to the polyhydroxy fatty acid amide class of nonionic surfactants. These surfactants have the advantage that they can be prepared using mainly renewable resources, such as fatty acid esters and sugars, and thereby provide substantial advantages to the formulators of detergent compositions who are seeking non-petrochemical, renewable resources for the manufacture of detersive surfactants. Moreover, the polyhydroxy fatty acid amides exhibit particularly good cleaning performance, especially when used in conjunction with various anionic surfactants. There is considerable impetus to begin using polyhydroxy fatty acid amide surfactants in commercial cleaning compositions of all types.
Unfortunately, many of the polyhydroxy fatty acid amide surfactants are suds boosters and stabilizers, especially when used in combination with conventional anionic surfactants. Accordingly, the formulator of low sudsing detergent compositions either must curtail the use of this desirable class of surfactants when formulating low sudsing detergents, or must use relatively high amounts of suds controlling agents in such compositions.
By the present invention, it has been unexpectedly determined that certain members of the class of polyhydroxy fatty acid amides provide good cleaning performance, but do not undesirably enhance sudsing. Indeed, it has been further discovered that the aforesaid "low sudsing" polyhydroxy fatty acid amide surfactants can actually diminish the sudsing of their counterpart high sudsing polyhydroxy fatty acid amide surfactants. This sub-class of low sudsing polyhydroxy fatty acid amides is employed in the practice of this invention to provide low sudsing compositions for use under circumstances where, as disclosed above, low sudsing is desired.